The present invention broadly relates to the process of replacing full bobbins by empty bobbins at a spinning machine and pertains, more specifically, to a new and improved method of automatically exchanging full bobbins for empty bobbins at a flyer, i.e. a flyer frame or roving frame. The present invention also relates to a new and improved apparatus for automatically exchanging full bobbins for empty bobbins at a flyer, i.e. a flyer frame or roving frame.
Generally speaking, the present invention relates to a new and improved method of the type as described and which method may encompass the steps of tilting the full bobbins out of their substantially vertical operating position into an inclined position, lifting the full bobbins in their inclined position to doff the full bobbins and bringing the full bobbins into a substantially vertical position. The method includes in analogous manner the steps of tilting the empty bobbins out of a substantially vertical position into an inclined position, lowering the empty bobbins in the inclined position and bringing the empty bobbins into their substantially vertical operating position. The replacement of full bobbins by empty bobbins is accomplished by a doffing apparatus separate from the flyer.
In a known apparatus for automatically doffing cops or full bobbins and replacing them with empty tubes, the predecessor of which is disclosed, for example, in U.S. Pat. No. 4,757,679, granted Jul. 19, 1988, the empty tubes are suspended at a carrier with integrated transit beam in the transport-starting position, the empty tubes having been transferred to the carrier from the suspension transport means arriving from a ring spinning machine. In substantially vertical downward travel, the carrier positions the empty tubes in two lengthwise rows at an interim or intermediate storing conveyor in the lower part of the roving frame and extending along the face of and substantially parallel to the latter, i.e. upon a conveyor comprising a plurality of pegs and displaceable by one half the longitudinal pitch between the axes of adjacent cops. The carrier is then again lifted. The conveyor is displaced by a half of the pitch with respect to the arrangement or layout of the full bobbins in the flyer. Substantially at the level of the flyer support bed, the flyer comprises a horizontally disposed guide bar which extends over the entire length of the machine and projects at one end therefrom by a certain distance, and a doffing carriage is mobile along the entire machine face by means of the aforesaid guide bar.
In the vertical position the doffing carriage is aligned with the interim or intermediate storing conveyor and can be brought by means of a lever construction into an inclined position in which it defines an acute angle to the flyer. In this inclined position the doffing carriage is aligned with a cop carrier which has been lowered from the operating or spinning position and tilted into an inclined position, and which cop carrier holds at spindles the full bobbins to be replaced by empty tubes. At the lower end of its pneumatic cylinder the doffing carriage has twelve gripping elements by means of which it doffs the full bobbins or cops from the cop carrier in groups and places them on the pegs of the interim storing conveyor between the empty bobbins or tubes which are already present thereupon. When the whole flyer has been cleared the interim storing conveyor is again displaced by a half pitch, i.e. by one half the longitudinal distance between the axes of adjacent full bobbins. The doffing carriage is now in a position to lift the empty bobbins or tubes by groups from the interim storing conveyor, to bring them into the inclined position and to deposit them onto the spindles at the cop carrier. The cop carrier with the complete number of empty bobbins or tubes again tilts into the substantially horizontal position and is vertically lifted into the correct position for commencement of spinning. The carrier then is again lowered in order to engage the full bobbins at the interim storing conveyor and to vertically convey them into their upper removal or discharge position. From this removal or discharge position the full bobbins or cops are plugged onto transport means by a pivotable lever arm in order to supply subsequent ring spinning machines with roving bobbins.
The mode of operation by groups of the doffing carriage, both for the full bobbins as well as for the empty bobbins, and the interim storing at the conveyor, lead to substantially long doffing times during which spinning cannot take place. Moreover, this known flyer doffer is relatively complicated and requires a corresponding constructional expenditure. The doffing carriage is displaced after use on the guide bar to one side out of the working range of the spindles and remains in this position on the flyer, whereby substantial space is required and accessibility is strongly impaired.